This invention relates to a method and apparatus for design of a prosthesis using optical surface topography mapping and, more particularly, to a scanning method and apparatus to measure a patient's residuum followed by the use of three-dimensional computer representation to create a three-dimensional design of the prothesis socket and the prosthesis itself.
Currently, the fabrication of most protheses is accomplished by one of two methods. The first method is manual and involves hand casting of the residuum by a skilled prosthetist. The second method involves hand casting of the residuum followed by tactile probe scanning and CAD/CAM (computer-aided design/computer-aided manufacturing) procedures. This method is preferable to the manual method primarily because it limits the fabrication time and results in a more accurate prosthesis fit.
The manual fabrication process normally requires at least 18-20 hours. The hand casting plus CAD/CAM method requires at least five hours. The prosthetist in either case may need to remake the prothesis several times to adjust areas that are uncomfortable to the patient. This occurs more frequently in the manual method.
Often, the fit of a prothesis manufactured under one of the current methods is poor and the prothesis is uncomfortable when the patient is walking because the prothesis has been fabricated from a plaster cast of a relaxed residuum rather than from a partially stressed residuum. Since the residuum is under stress while a patient is walking, it is understandable that a prosthesis designed and manufactured from a plaster cast of a relaxed residuum would produce an uncomfortable and wholly inadequate prosthesis.